METHOD FOR PRODUCING CROSS-LINKABLE MATERIALS BASED ON ORGANYLOXYSILANE-TERMINATED POLYMERS

Abstract

A method for producing crosslinkable compositions (M) by mixing (A) 100 parts by weight of compounds of the formula Y[(CR.sup.1.sub.2).sub.bSiR.sub.a(OR.sup.2).sub.3-a].sub.x (I) and (B) 0.1 to 75 parts by weight of at least one thixotropic agent. The at least one thixotropic agent is selected from fatty acid amides, polyamide waxes, polyamide wax derivatives, hydrogenated castor oil, hydrogenated castor oil derivatives, polyester amides, polyureas, oxidized polyethylenes and metal soaps and optionally further components. The period of time from the start of the mixing step of (A) and (B) to the end of storage of the crosslinkable composition (M) is at least 7 days and during this period all process steps are carried out at temperatures below 59 C.

Claims

1-9. (canceled)

10. A method for producing crosslinkable compositions (M) by mixing (A) 100 parts by weight of compounds of the formula
Y[(CR.sup.1.sub.2).sub.bSiR.sub.a(OR.sup.2).sub.3-a].sub.x(I), wherein Y is an x-valent polymer radical bonded via nitrogen, oxygen, sulfur or carbon, R may be the same or different and is a monovalent, optionally substituted hydrocarbon radical, R.sup.1 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbon radical which can be attached to the carbon atom via nitrogen, phosphorus, oxygen, sulfur or a carbonyl group, R.sup.2 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbon radical, x is an integer from 1 to 10, a may be the same or different and is 0, 1 or 2 and b may be the same or different and is an integer from 1 to 10, and (B) 0.1 to 75 parts by weight of at least one thixotropic agent selected from fatty acid amides, polyamide waxes, polyamide wax derivatives, hydrogenated castor oil, hydrogenated castor oil derivatives, polyester amides, polyureas, oxidized polyethylenes and metal soaps and optionally further components, optionally further subsequent process steps and subsequent storage of the resulting mixture (M), wherein the period of time from the start of the mixing step of (A) and (B) to the end of storage of the crosslinkable composition (M) is at least 7 days and during this period all process steps are carried out at temperatures below 59 C.

11. The method as claimed in claim 10, wherein all process steps are carried out at temperatures below 49 C.

12. The method as claimed in claim 10, wherein the storage is carried out at a temperature of 20 to 45 C.

13. The method as claimed in claim 10, wherein component (B) is a polyamide wax or polyamide wax derivative.

14. The method as claimed in claim 10, wherein component (B) is a polyamide wax.

15. The method as claimed in claim 10, wherein all process steps are carried out at temperatures which are at least 30 C. below the melting point of the component (B) used, where, if two or more thixotropic agents (B) are used, this specification refers to that thixotropic agent (B) having the highest melting point.

16. The method as claimed in claim 10, wherein (A) 100 parts by weight of compounds of the formula (I), (B) 0.1-50 parts by weight of thixotropic agent, (C) 0.1-25 parts by weight of organosilicon compounds comprising units of the formula
D.sub.eSi(OR.sup.4).sub.dR.sup.3.sub.cO.sub.(4-c-d-e)/2(II), where R.sup.3 may be the same or different and is a monovalent, optionally substituted SiC-bonded, nitrogen-free organic radical, R.sup.4 may be the same or different and is a hydrogen atom or optionally substituted hydrocarbon radicals, D may be the same or different and is a monovalent, SiC-bonded radical having at least one nitrogen atom not bonded to a carbonyl group (CO), c is 0, 1, 2 or 3, d is 0, 1, 2 or 3 and e is 0, 1, 2, 3 or 4, with the proviso that the sum of c+d+e is less than or equal to 4 and at least one radical D is present per molecule, optionally (D) non-reactive plasticizers, optionally (E) fillers, optionally (F) silicone resins optionally (G) catalysts, optionally (H) adhesion promoters, optionally (I) water scavengers, optionally (J) additives and optionally (K) additional materials are mixed together and then the resulting mixture is stored for at least 7 days, all process steps being carried out at temperatures below 59 C.

17. The method as claimed in claim 10, wherein filling is carried out at a time when the composition (M) at 25 C. has a viscosity measured in accordance with DIN 54458 with a deformation of 100% which is at least a factor of 1.5 below the viscosity measured under identical conditions which the same composition (M) has reached after storage of 21 days at 23 C. after preparation thereof.

18. The method as claimed in claim 10, wherein filling is carried out at a time when the composition (M) at 25 C. has a viscosity measured in accordance with DIN 54458 with a deformation of 0.1% which is at least a factor of 2 below the viscosity measured under identical conditions which the same composition (M) has reached after storage of 21 days at 23 C. after preparation thereof.

Description

EXAMPLE 1: PREPARATION OF AN ELASTIC ADHESIVE FORMULATION

[0224] 180 g of a polypropylene glycol silane-terminated on both sides having an average molar mass (M.sub.n) of 18 000 g/mol and end groups of the formula OC(O)NH(CH.sub.2).sub.3Si(OCH.sub.3).sub.3 (commercially available under the name GENIOSIL STP-E35 from Wacker Chemie AG, D-Munich) are homogenized in a laboratory planetary mixer from PC-Laborsystem, equipped with a cross-arm mixer and a dissolver, for 2 minutes with the cross-arm mixer at 200 rpm at ca. 25 C., with 250 g of diisoundecyl phthalate as plasticizer, 224 g of a precipitated chalk coated with fatty acid having an average particle diameter (D50%) of ca. 0.07 m (commercially available under the name Hakuenka CCR S10 from Shiraishi Omya GmbH, AT-Gummern), 224 g of a calcium carbonate coated with stearic acid having an average particle diameter (D50%) of ca. 2.0 m (commercially available under the name Omyabond 520 from Omya, D-Cologne), 40 g of a titanium dioxide having a TiO.sub.2 content >92.0%, a standard classification according to DIN EN ISO 591 of R2, the color index Pigment White 6, and a bulk density of 3.9 kg/I and an oil absorption of 19 g/100 g (commercially available under the name Kronos 2360 from Kronos, USA Dallas) and 40 g of a micronized polyamide wax having a melting point of 117-127 C. (commercially available under the name Crayvallac SLX from Arkema, France). The mixture is then stirred for 15 minutes at 600 rpm with the cross-arm mixer and 1000 rpm with the dissolver. The mixture heats up to ca. 43 C. due to the stirring energy introduced. It is then cooled again to 25 C.

[0225] Subsequently, 10 g of a stabilizer mixture containing a hindered amine light stabilizer (HALS) and a UV absorber (commercially available under the name GENIOSIL Stabilizer F from Wacker Chemie AG, D-Munich), 20 g of vinyltrimethoxysilane (commercially available under the name GENIOSIL XL 10 from Wacker Chemie AG, D-Munich) and 2 g of dioctyltin dilaurate (commercially available under the TIB Kat 216 from TIB Chemicals AG, D-Mannheim) are stirred in for 2 minutes with the cross-arm mixer at 600 rpm and 1000 rpm with the dissolver. There is no appreciable heating of the mixture. Finally, 10 g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (commercially available under the name GENIOSIL GF 9 from Wacker Chemie AG, D-Munich) are stirred in for 2 minutes at 600 rpm with the cross-arm mixer and 1000 rpm with the dissolver. Here, too, there is no appreciable heating of the mixture.

[0226] Finally, the mixture is homogenized and stirred bubble-free for 1 minute at 600 rpm with the cross-arm mixer and for 1 minute at 200 rpm with the cross-arm mixer at a pressure of ca. 100 mbar.

[0227] The composition thus obtained is filled into 310 ml PE cartridges, sealed airtight and stored for 3 weeks at 23 C. prior to testing.

EXAMPLE 2

[0228] The procedure is as described in Example 1, except that the finished cartridge is stored at 8 C. for 3 weeks prior to testing.

COMPARATIVE EXAMPLE 1 (C1)

[0229] The procedure is as described in Example 1, except that the bubble-free stirred material obtained is used directly in the tests described in Example 3 without any storage.

COMPARATIVE EXAMPLE 2 (C2)

[0230] The procedure is as described in Example 1, except that the finished cartridge is stored at 23 C. for only 24 h prior to the tests described in Example 3.

COMPARATIVE EXAMPLE 3 (C3)

[0231] The procedure is as described in Example 1, except that the finished cartridge is initially stored at 80 C. for 3 h and then at 23 C. for 3 weeks prior to testing.

COMPARATIVE EXAMPLE 4 (C4)

[0232] The procedure is as described in Example 1, except that the finished cartridge is initially stored at 110 C. for 3 h and then at 23 C. for 3 weeks prior to testing.

COMPARATIVE EXAMPLE 5 (C5)

[0233] The procedure is as described in example 1, except that in the first mixing step after the addition of the polyamide (Crayvallac SLX), the mixture is heated to 80 C. using an external heater and the temperature is maintained for 15 min. All other steps are identical, and also in this case, the finished cartridge is stored for 3 weeks at 23 C.

EXAMPLE 3: DETERMINATION OF THE PROPERTIES OF THE SAMPLES FROM EXAMPLES 1 AND 2 AND COMPARATIVE EXAMPLES (C1) TO (C4)

[0234] Skin Formation Time (SFT)

[0235] To determine the skin formation time, the crosslinkable compositions obtained in the examples are applied in a 2 mm thick layer on PE film and stored at standard conditions (23 C. and 50% relative humidity). During curing, the formation of a skin is tested every 5 minutes. For this purpose, a dry laboratory spatula is carefully placed on the surface of the sample and pulled upwards. If the sample sticks to the finger, no skin has yet formed. If no sample remains stuck to the finger, a skin has formed and the time is noted. The results are found in Table 1.

[0236] Mechanical Properties

[0237] The compositions were each spread on milled-out Teflon panels to a depth of 2 mm and cured for 2 weeks at 23 C., 50% relative humidity.

[0238] The Shore A hardness is determined according to DIN EN 53505.

[0239] The tensile strength is determined according to DIN EN 53504-S1.

[0240] The elongation at break is determined according to DIN EN 53504-S1.

[0241] The 100% modulus is determined according to DIN EN 53504-S1.

[0242] The results are found in Table 1.

[0243] Rheological Properties

[0244] The viscosity at 0.1% deformation is determined according to DIN 54458 at 25 C.

[0245] The viscosity at 100% deformation is determined according to DIN 54458 at 25 C.

[0246] The results are found in Table 1.

TABLE-US-00001 TABLE 1 Composition of example 1 2 C1 C2 C3 C4 C5 SFT [min] 14 13 14 15 12 12 13 Shore A hardness 45 47 46 45 44 47 46 Tensile strength [N/mm.sup.2] 1.7 1.6 1.7 1.7 1.7 1.6 1.7 Elongation at break [%] 229 238 231 266 245 238 243 100% Modulus [MPa] 1.1 1.0 1.1 1.1 1.0 1.0 1.1 Viscosity at 0.1% deformation [Pas] 8930 5170 550 650 8780 7610 1860 Viscosity at 100% deformation [Pas] 93 72 18 20 94 94 38

[0247] It has been shown that the compositions according to the invention develop thixotropic properties even without thermal treatment during the long storage period according to the invention, which are in no way inferior to the properties of thermally treated compositions and in some cases are even superior.

[0248] At the same time, the results of comparative examples C1 and C2 show that when the material according to the invention is filled into a container for final application, for example a cartridge, within 24 hours of production thereof, it has a significantly lower viscosity at the time of filling, both at high and low shear, than at the time of its application, which is carried out only after the storage period according to the invention.

EXAMPLE 4: PREPARATION OF A LOW-MODULUS SEALANT FORMULATION

[0249] 100 g of a polypropylene glycol silane-terminated on both sides having an average molar mass (M.sub.n) of 18 000 g/mol and end groups of the formula OC(O)NH(CH.sub.2).sub.3Si(OCH.sub.3).sub.3 (commercially available under the name GENIOSIL STP-E35 from Wacker Chemie AG, D-Munich) are homogenized in a laboratory planetary mixer from PC-Laborsystem, equipped with a cross-arm mixer and a dissolver, for 2 minutes with the cross-arm mixer at 200 rpm at ca. 25 C., with 223 g of diisononyl cyclohexane-1,2-dicarboxylate as plasticizer (commercially available under the name Hexamoll DINCH from BASF SE; D-Ludwigshafen), 261 g of a calcium carbonate coated with stearic acid having an average particle diameter (D50%) of ca. 2.0 m (commercially available under the name Omyabond 520 from Omya, D-Cologne), 261 g of an ultrafine calcium carbonate coated with fatty acid having a primary particle size of ca. 30 nm (commercially available under the name Viscoexel 30 from Shiraishi Omya GmbH, A-Gummern) and 30 g of a micronized polyamide wax having a melting point of 117-127 C. (commercially available under the name Crayvallac SLX from Arkema, France). The mixture is then stirred for 15 minutes at 600 rpm with the cross-arm mixer and 1000 rpm with the dissolver. The mixture heats up to ca. 41 C. due to the stirring energy introduced. It is then cooled again to 25 C.

[0250] Subsequently, 100 g of a one-sided silane-terminated polypropylene glycol having an average molar mass (M.sub.n) of 5000 g/mol and end groups of the formula OC(O)NH(CH.sub.2).sub.3Si(OCH.sub.3).sub.3 (commercially available under the name GENIOSIL XM 25 from Wacker Chemie AG, D-Munich), 5 g of a stabilizer mixture containing a hindered amine light stabilizer (HALS) and a UV absorber (commercially available under the name GENIOSIL Stabilizer F from Wacker Chemie AG, D-Munich), 15 g of vinyltrimethoxysilane (commercially available under the name GENIOSIL XL 10 from Wacker Chemie AG, D-Munich) and 2 g of a dioctyltin-silane complex (CAS No.: 870 08-6, commercially available under the name TIB Kat 417 from TIB Chemicals AG, D Mannheim) are stirred in for 2 minutes at 600 rpm with the cross-arm mixer and 1000 rpm with the dissolver. There is no appreciable heating of the mixture. Finally, 3 g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (commercially available under the name GENIOSIL GF 9 from Wacker Chemie AG, D-Munich) are stirred in for 2 minutes at 600 rpm with the cross-arm mixer and 1000 rpm with the dissolver. Here, too, there is no appreciable heating of the mixture.

[0251] Finally, the mixture is homogenized and stirred bubble-free for 1 minute at 600 rpm with the cross-arm mixer and for 1 minute at 200 rpm with the cross-arm mixer at a pressure of ca. 100 mbar.

[0252] The composition thus obtained is filled into 310 ml PE cartridges, sealed airtight and stored for 3 weeks at 23 C. prior to testing.

COMPARATIVE EXAMPLE 6 (C6)

[0253] The procedure is as described in example 3, except that in the first mixing step after the addition of the polyamide (Crayvallac SLX), the mixture is heated to 80 C. using an external heater and the temperature is maintained for 15 min. All other steps are identical, and also in this case, the finished cartridge is stored for 3 weeks at 23 C.

EXAMPLE 5: DETERMINATION OF THE PROPERTIES OF THE SAMPLES FROM EXAMPLE 4

[0254] Skin formation time, mechanical and rheological properties are determined as described in Example 3. The results are found in Table 2.

TABLE-US-00002 TABLE 2 Composition of example 4 C6 SFT [min] 36 31 Shore A hardness 24 19 Tensile strength [N/mm.sup.2] 0.9 0.9 Elongation at break [%] 622 669 100% Modulus [MPa] 0.3 0.4 Viscosity at 0.1% deformation [Pas] 5940 5970 Viscosity at 100% deformation [Pas] 78 80

[0255] It is again shown that the composition according to the invention from example 3 develops thixotropic properties even without thermal treatment during the long storage period according to the invention, which are in no way inferior to the properties of thermally treated composition in comparative example C6.